In a project such as a software development, confidential work and the other normal work are often performed with one computer due to a problem of a cost or a computer arrangement space. For this reason, both of information for the project and information for the normal work are stored in the same computer.
In order to prevent the confidential information from leaking, it is needed to encrypt information during the confidential work and delete the information after the completion of a series of confidential works. However, as described above, since the confidential information and the other information are mixed in one computer, it is difficult to determine which information should be encrypted and deleted. In order to resolve this problem, the following technologies are known.
For example, a system is known which changes contents of files to be disclosed, according to the authority of each user, and prevents confidential information from leaking to a user having the low authority. Therefore, the user who has the high authority performs the confidential work and the user who has the low authority performs the normal work, and confidential information and information pertinent to the normal work can be discriminated (for example, refer to Patent Document 1).
By using multibooting to switch a starting OS or a virtual machine, an OS and information that are used for the normal work and an OS and information that are used for the project can be classified (for example, refer to Patent Document 2 and Non-Patent Document 1).